Safety stop mechanism.



A. J. NICHT.

SAFETY STOP MECHANISM.

APPLICATION FILED APR. 17. 1912.

Patented Dec. 7, 1915.

2 SHEETS-SHEETK.

COLUMBIA PLANOORAPH 60.,WA5MIROTON, D c

A. J. NICHT.

SAFETY STOP MECHANISM.

APPLICATION FILED APR.17, I912.

Patented Dec. 7, 1915.

2 suzsTs-snan 2.

COLUMBIA PLANOORAI'N 00., WASHINGTON, n. 1:.

ALEXANDER J. NIGHT, or cnIcAeo, ILLINOIS, Assrenon, BY MESNE ASSIGNMENTS, T0 ALLIS-GHALMERS MANUFACTURING COMPANY, A conrona'rroiv or DELAWARE.

SAFETY STOP MECHANISM.

Specification of Letters Patent.

Patented Dec. '7, 19.15.

Application fil ed April 17, 1912. Serial No. 691,519.

To all whom it may concern:

Be it known that I, ALEXANDER J. NIoH'r, a citizen of the United States, residing at Chicago, in the county of Cook and State of Illinois, have invented certain new and useful Improvements in Safety Stop Mechanism, of which the following is a full, clear, and eXact specification.

This invention relates to protective devices, and more particularly to overwind devices used in connection with hoisting apparatus.

In the operation of hoistsof various types, the operator, under normal operating conditions, stops the car or skip at the proper limits, or if the hoist works automatically the car or ship is provided. with means to cause said car or skip to stop at the proper limits. But if the operator is negligent or the hoist gets out of order, there is more or less danger in the operation thereof, in that the car or skip might overrun its limits, causing injurious results not only to the hoist but to human life. I

It is therefore the object of my invention to provide hoists of various typeswith improved means to prevent the continued operation of such hoists in the same direction after such hoists have reached or passed certain predetermined limits of travel.

The various novel features of my invention will be apparent from the description and drawings and will be particularly pointed out in the claims.

The invention is illustrated on the accompanying sheets of drawings, in which Figure l is a rear elevation of a dial indicator embodying my invention which includes a control switch, the control switch being in its normal or closed position; Fig. 2 is a side elevation of the same dial indicator shown in Fig. 1; Fig. 3 is a rear eleva tion of the same dial indicator, the control switch being in open position; Fig. 4: is a front elevation of the control switch with attachments forming a part of my invention; and, Fig. 5 is a diagram showlng the control switch in circuit with a no-voltage magnet of a circuit-breaker.

In the operation of hoists of various types, it is customary to provide indicating apparatus to show the location of the hoist car or skip at all times. These indicators may be of different types, but I have illustrated my invention in this particular case in connection with indicators of the dial type. The indicator proper is mounted upon any suitable pedestal or support 10 having a base portion 11 upon which is mounted a casting 12 having two beari11gs13 and14: disposed at right angles with respect to each other. In one of the bearings 13 is a shaft 15 which is adapted to be rotated. Mounted upon this shaft 15 is a gear wheel 16 which may be connected to the hoist in any manner whatsoever to transmit motion fromthe hoist to the indicator under all conditions of operation. Also mounted upon the shaft 15 and rotatable therewith is a worm 17 meshing with and adapted to actuate a gear wheel 18 which is mounted upon and secured to a shaft 19 rotatable in the bearing 14. At one end of the shaft 19 there is secured an indicator pointer 20 which moves relative to a suitable dial 21 secured to one end of ture, secured to which, or integrally formed 4 therewith, is a cam 28. A roller 29 secured in one end of an arm 30 is adapted to ride on the cam surface for actuating the movable contact 31 of a control switch 32. This switch is normally biased to closed position by a spring 33 and is preferably located in a control circuit indicated by the leads 34:

and 35 respectively connected to the movable and stationary contact members of the switch. This switch is preferably located in circuit with a no-voltage magnet controlling a circuit-breaker through which current is supplied to a motor for operating the hoist.

Under normal operating conditions as the hoist car or skipis raised and lowered between its upper and lower limits the indicator pointer 20 moves relative to the dial to indicate the location of the car or skip. At the same time the member 22, which is secured to the same shaft 19 to which the indicator pointer 20 is secured, moves in the same sense with the indicator pointer, but under normal conditions its projection 23 does not pass into engagement with the pro jection 2a of the segmental gear member 25. So under normal operating conditions the safety switch 32 and some of its cooperating parts are not caused to operate. But if the hoist car or skip should move beyond one of its limits the projection 23 of member 22 will be forced into engagement with projection 24 of the segmental gear member causing said gear member to rotate gear 27 with the cam member. Due to the movement of this cam member the switch arm 30 is moved counter-clockwise with a quick movement for opening the control switch 32 for the purpose of preventing further movement of the hoist car or skip in the same direction. The pointer 20, intermeshing gears 25 and 27 cam member 28, and switch arm 30 are so proportioned and arranged relatively to each other that for a very slight movement of the indicator pointer 20 and accordingly a slight movement of the hoist car or skip, a comparatively large and quick movement of the cam 28, switch arm 30, and movable switch member 31 is efiected. In other words, when the hoist car or skip has gone beyond one of its limits a very short distance, whichmay be of any desirable value, the switch iscaused to open immediately to prevent further movement of such car or skip.

There may be various modifications and arrangements other than that here shown and described, and it is my intention to cover all such modifications and arrangements which do: not depart from the spirit and. scope'of my invention set forth in the appended claims.

What'I claim as new is:

1.. In an overwind device, the combination of an indicator pointer, a shaft on which said pointer is mounted, a member also mounted on said shaft and movable with said pointer, a segmental gear actuatable by said member, a gear having a cam portion and meshing with said segmental gear, an

arm movable by said cam, and a control switch actuated in response to the movement of said arm.

2. In an overwind device, the combination of an indicator pointer, a member movable with said pointer, a gear actuatable by said member, another gear having a cam member and meshing with said first gear, an arm movable by said cam, and a control switch operated in response to movements of said arm.

3. In an overwind device, the combination of an indicator pointer, a member movable with said indicator pointer, a ear having a projection lying in the path of said member for receiving motion therefrom, a cam member movable through said gear, and a switch operated to open and closed positions in re sponse to movement of said cam member.

4. In an overwind device, a casting having-two bearings disposed at right angles with respect to each other, a shaft having a worm rotatable in one of said bearings, a shaft having a gear actuated by said worm and being rotatable in said other bearing, an indicator pointer on said second shaft, a member mounted on said second shaft, a gear member lying in the path of said member and actuatable thereby, a cam member actuatable by said gear member, and a control switch operated in response to the move ments of said cam'member.

5. 'In an overwind device for hoists, a control switch, an element operable with the hoist to indicate the position thereof at any time, a member actuatable by said indicating element only during the final portion of the travel of the hoist, and operating means comprising a coacting cam and lover actuatable by said member and effective to cause actuation of said control switch.

In testimony whereof I aflix my signature, in the presence of two witnesses.

ALEXANDER J. NIGHT.

.vVitnesses:

HENRY RUDE, J. H. Grow.

Copies of this patent may be obtained for five cents each, by addressing the Commissioner of Patents,

- Washington, D. C. 

